In various electronic circuits, for example a controller for a safety unit in utility vehicles, a protection circuit may be used to avoid excessively high voltages on connections of integrated circuits. In this case, it may not be possible to test whether this protection circuit is still functional over the course of time or has lost its function owing to corrosion or other environmental influences. If the protection circuit is no longer functional, this cannot be verified in the prior art and there is only assumed protection against such excessively high voltages on connections of the integrated circuit. In the event of excessively high voltages actually occurring on connections of integrated circuits, this means that the protective function of this protection circuit is no longer ensured, with the result that the integrated circuit may possibly be damaged in this case, despite the provision of the protection circuit.